The market share of CDHPs or consumer directed health plans- plans with high deductibles and personal health accounts has grown dramatically in recent years. CDHPs change incentives for use of preventive services in complex ways. CDHPs provide first dollar coverage for a few selected primary preventive services such as cancer screenings but CDHP enrollees pay the full costs for other preventive services such as the costs of prescription drugs below the annual deductible. Consumers also face higher costs other medical expenses such as hospitalizations which might be prevented by efficient use of preventive. The proposed research project would be the first, to our knowledge, to comprehensively estimate the longer-term effects of CDHPs on use of primary and secondary preventive services, and whether these health plans lead to greater price-shopping for preventive care. We will utilize unique claims and survey data from CDHP and traditional plans offered by 63 large U.S. firms for the period 2003-2007 to: 1) Examine the long-term effects of CDHPs on the use of preventive services with first dollar coverage, such as screenings and immunizations. 2) Examine the effects of CDHPs on the use of preventive services without first dollar coverage, such as prescription drugs for secondary prevention of diabetes, hypertension, and coronary heart disease. 3) Examine the effects of CHDPs on price shopping for preventive services including services with and without first dollar coverage.